1. Field of the Invention
This invention relates to an intaglio printing press having an ink recovery function.
2. Description of the Related Art
Intaglio printing is a printing method which uses a plate having image areas formed to be concave relative to non-image areas (i.e., intaglio plate). In this type of printing, ink is filled throughout the plate, then ink in the non-image areas is wiped off to leave ink only in the image areas, and then paper is strongly pressed against the plate to transfer ink remaining in the image areas to the paper.
An example of an intaglio printing press used in the intaglio printing is shown in FIG. 10. In the drawing, arrows show the direction of rotation of a cylinder or roller.
Reference numeral 101 denotes an intaglio cylinder, which is in contact with an impression cylinder 102. An intaglio plate, which is formed from a flat smooth surface as non-image areas and depressions as image areas, is mounted around the intaglio cylinder 101. A plurality of inking devices 103 are provided on one side of the intaglio cylinder 101. Pattern rollers 104, which are ink form rollers of the inking devices 103, are in contact with the intaglio cylinder 101. Ink fountain rollers 106 of ink fountains 105, where inks of different colors are stored, are in contact with the pattern rollers 104. The pattern roller 104 has a convex pattern portion formed on the surface so that ink supplied to the pattern roller 104 is supplied only to those parts of the intaglio plate which are to be supplied with ink of the relevant color. That is, the ink fountain roller 106 transfers ink only to the convex pattern portion of the pattern roller 104, and the ink is transferred from this pattern portion to predetermined locations (image areas and non-image areas) of the intaglio plate.
A wiping device 107, as an ink removing device, is provided ahead of the site of contact between the intaglio cylinder 101 and the impression cylinder 102, and laterally of the intaglio cylinder 101. A wiping roller 108 of the wiping device 107 is in contact with the intaglio cylinder 101. The wiping roller 108 wipes off a surplus ink from the intaglio plate. That is, ink remains only in the image areas of the intaglio plate. The wiping roller 108 is soaked in a cleaning solution 110 within a cleaning tank 109.
(Alternatively, the surface of the wiping roller 108 is sprayed with the cleaning solution by a spray.) The ink wiped off is cleaned off by a cleaning unit (not shown) in contact with the wiping roller 108 within the cleaning solution 110.
A sheet 111 is supplied between the intaglio cylinder 101 and the impression cylinder 102. The sheet 111 is strongly pressed against the intaglio plate of the intaglio cylinder 101 by the impression cylinder 102, whereby ink in the image areas of the intaglio plate is transferred to the sheet 111. A so-called intaglio-printed sheet is transported to a delivery unit, not shown, by a delivery device (delivery chain) 112.
As stated earlier, the surplus ink of the ink supplied to the intaglio plate is wiped off by the wiping roller 108. However, the surplus ink is not sufficiently wiped off by the wiping roller 108 alone. Thus, as disclosed in Japanese Patent Publication No. 1990-42070 (column 6, drawing), a prewiping roller constituting a prewiping device as an ink removing device may be provided ahead (upstream) of the wiping roller 108 to wipe off the surplus ink before it is wiped off by the wiping roller 108.
The amount of ink wiped off by the wiping roller 108 is considerable, and thus its recovery has been desired. Particularly, recovery of ink of a color used in a large amount, and recovery of expensive ink have been desired.
However, if ink is removed by soaking of the wiping roller 108 in the cleaning solution, the ink mixes with the cleaning solution, and is no longer separable for recovery, and has thus been discarded. Even in Japanese Patent Publication No. 1990-42070, only prewiping is performed, and a prewiped ink is considered to have been discarded.
Thus, it is attempted to recover ink before being wiped off by the wiping roller 108. Currently, recovery of ink is performed by an operator, who uses a spatula or the like to scrape off the ink transferred from the surface of the intaglio plate to the surface of a roller or the like, and returns the ink to the ink fountain 105.
However, this ink recovery operation requires the operator to use a spatula inside a narrow printing press to scrape off the ink. Thus, this operation is complicated, and imposes a heavy burden on the operator, thereby presenting problems of taking a make-ready time and decreasing productivity. Even with a structure in which the recovered ink is stored in a catch pan within the printing press, this catch pan has to be mounted inside and detached from the printing press, thereby imposing a heavy load on the operator.